Switchgear are provided in a number of different types of equipment in power transmission, distribution and supply systems, for instance in low voltage contactors.
It is known to provide switchgear with arc chutes comprising parallel splitter plates separated by air gaps in one or two groups on two sides of a moveable bridging element that interconnects two conductors. After the arc has been extinguished in the switchgear, a transient recovery voltage is applied across the parallel splitter plates.
Splitter plates are also known to be used for splitting an arc into partial arcs. This is as an example disclosed in WO 2016/091318. WO 2016/091318 also discloses the use of low ohmic resistors connected between the splitter plates for commutating circuit current into the resistors near the moment of current zero crossing. Thereby the air gap of the arc chute can cool down for a while and the dielectric strength may increase to improve the arc breaking performance.
There is one problem with a switchgear with arc chutes comprising parallel splitter plates and that is that a glow discharge may occur across one or more of the air gaps after the current interruption. The glow discharge may introduce more voltage stress across the other air gaps, which may in turn lead to an increase in the risk of arc re-ignition.
The present invention is directed towards the solving of the problem of glow discharges and the increased risk of arc re-ignition.